Another sanity check and possibly stupid question ...

[dmr]

I'm wondering if anybody has seen this before ...

I'm now on day 6 of resurrecting a trashed Mamiya SD. I was ALMOST ready to actually run a test roll -- I actually picked up a couple 12 exposure rolls yesterday -- when I noticed a couple things didn't look right.

First, it didn't sound right when I wound and cocked the shutter. Like it didn't "catch" maybe 1 out of 10 times. I figured (and still do) that it's a minor linkage problem, so I pulled the bottom place off and watched the lever turn the gear to cock the shutter and such when I noticed something that really appears wrong.

The entire lens assembly is tilted slightly, meaning out of square with the body. Well, not the whole thing, everything front of the focus ring seems to be tilted. 🙁 At first I thought I was imagining this, but I measured and it sure is.

When you look from the top of the camera, it leans to the left. The left side of the filter screw ring is about 1.5 to 2 mm closer to the camera body than the right side. I don't have calipers or dividers. This is just measuring with the ruler flat against the plate that mounts the lens assembly and sighting the top. It's definitely off. I measured several times.

Has anybody ever seen anything like this?

My first idea (which I have not dismissed, but ...) is that it was dropped or smacked, but I can't find any obvious (or even non-obvious) impact damage anywhere. I had everything in front of the focus helix apart, and everything went back together tight and solid. I did tighten the ring that connects the focus helix to the shutter, but I didn't pull that all apart. Again, it was solid and tight.

I know that a 1.5-2mm tilt here is going to throw off the plane of focus! I don't really know how much, but I do know that it's not supposed to be that way.

I'm right now taking a deep breath and preparing to take it apart again to see what exactly is bent or not together properly. (I'm glad I resisted the temptation to use contact cement on the leatherette!) I'm just wondering if anybody else has seen things like this.

Thanks again, everybody.

 

[jlw]

I've seen that kind of thing on various leaf-shutter cameras, usually from impact damage. If the camera takes a square hit on the front lens ring, for example, it can distort the shutter base (my term for the part into which the optical section screws) without showing much or any impact damage on the exterior parts. The lens cells still will screw easily into the attaching threads; it's just that the threads now are at an angle rather than being perpendicular to the shutter base, so everything forward gets distorted by the same amount. Often the shutter base is made of fairly soft metal, so it doesn't take much force to deform it.

 

[dmr]

I've seen that kind of thing on various leaf-shutter cameras, usually from impact damage. If the camera takes a square hit on the front lens ring,

Okay, this makes sense. 🙁 I'm looking at the front lens ring thing right now and I don't see any impact marks, but this did not come with a lens cap so maybe that took the shock and did not survive. 🙁

for example, it can distort the shutter base (my term for the part into which the optical section screws) without showing much or any impact damage on the exterior parts. The lens cells still will screw easily into the attaching threads;

And it does screw in and out freely, but at an angle. However, the shutter speed and aperture rings are at the angle too. I don't have the shutter off of the focusing helix yet, so I have a feeling that you may be right that the shutter itself is what is bent. I should know for sure as soon as I get it the rest of the way apart.

Thanks for the response, and congratulations! 🙂

 

[Pherdinand]

I would still run that roll of film through it, to see how serious the effect of this is.
OTOH, i'm sorry to hear this. These damages are the ones very difficult to repair.

 

[dmr]

I would still run that roll of film through it, to see how serious the effect of this is.
OTOH, i'm sorry to hear this. These damages are the ones very difficult to repair.

Well {grumble - profanity} it looks like this one, at least this shutter, will not be seeing a roll of film. 🙁

I've got the thing about as far apart as I can get it, and looking at the shutter assembly crosswise, the threaded part, the male threads that connect to the focus helix, are definitely bent out of square. 🙁 There's also a gap between the one plate on one side and the body of the shutter. It's definitely been damaged. 🙁

That's the bad news.

The good news is that I saw another one of these on that auction site over the weekend and snapped it up. Not as cheap as this one, but I figure unless they are both messed up in the exact same manner I can put the best of 2 together into one big frankencamera. 🙂 The glass on this one is very clean and I'm very proud of myself for getting the electronics cleaned up and working so well -- it passed the sunny-16 test out the window and almost agreed (maybe 1/2 stop off) with the Pentax. In low light, my "test box", actually the wall of the bathroom with both the overhead and vanity lights on dimmers, it was right on compared to the Pentax! The rest of the shell looks fine and the film advance and such are all smooth.

I think the best thing is to think of this as an educational investment and use this one as parts for the other one -- maybe vice versa, depending on how bad it is. 🙂

Thanks again, everybody, for the help and encouragement. 🙂

 

[jlw]

I've got the thing about as far apart as I can get it, and looking at the shutter assembly crosswise, the threaded part, the male threads that connect to the focus helix, are definitely bent out of square.

Hey, a lot of people have to pay big bucks for a tilt lens; you've got one at no extra charge!

As long as it works, in the unlikely event that anyone notices, you can say, "Yes, I had a machinist adjust it to exactly this angle for optimum Scheimpflug effect . I've got this other one that I use for regular perpendicular pictures."

Okay, seriously, it sounds as if you had good luck in picking up another one, and now you should have enough parts to build one good one with lots of spares left over.

It's a bummer how easy it is for these shutter bases to get distorted. Often it happens when the camera tips over on a tripod or something like that -- the impact is distributed over the whole front of the lens, so there may not be any visible damage, but the "cup" housing the shutter will be pushed out of shape (usually they're fairly soft aluminum.) Sometimes it's possible to remove the guts and straighten it again with some judicious tapping, but the metal will have lost its strength and it's likely to fold again if subjected even to a moderate whack.

 

[dmr]

Hey, a lot of people have to pay big bucks for a tilt lens; you've got one at no extra charge!

Yeah, uh, right ... LOL! 🙂

As long as it works, in the unlikely event that anyone notices, you can say, "Yes, I had a machinist adjust it to exactly this angle for optimum Scheimpflug effect . I've got this other one that I use for regular perpendicular pictures."

I assume this is similar to the tilt and swing of a view camera, something I've never used, and probably won't. 🙂

Okay, seriously, it sounds as if you had good luck in picking up another one, and now you should have enough parts to build one good one with lots of spares left over.

Yes, assuming the one part of the new one is good, I'm confident enough that I can make one good one out of two bad ones. Just so the shutter assembly itself is good, I should be OK.

Thanks again, everybody! 🙂